The proposed three-year project will enhance our understanding of the link between school absences, school absences due to influenza like illness and influenza incidence in the wider community. Our proposal extends an existing set of projects that the co-Investigators of this proposal have conducted on influenza in school-children in the Pittsburgh area in the last 5 years. The Pittsburgh Influenza Prevention Project and the Social Mixing and Respiratory Transmission in Schools project have allowed us to fine tune surveillance systems for absenteeism and respiratory illness in the Pittsburgh area. We have conducted absentee surveillance and performed laboratory investigations of the viral etiology of respiratory illness in over 6000 children over 3 years as part of these two studies. We propose to conduct cause-specific school absence surveillance in three school districts including 11,000 students in and around Pittsburgh, PA. We will include multiple levels of surveillance including web-based surveys targeted broadly, closer follow-up and determination of viral etiology of respiratory infections in a subset of schools and close observation of a sentinel cohort of 250 school children each year. Drawing upon existing methodological work on time series and studies of spatial-temporal patterns of infectious disease, we will develop new statistical models of community metrics of influenza incidence using cause- specific school absence data and other covariates. We have been engaged in research and collaboration with the Allegheny County Health Department and the Pennsylvania Department of Health for several years in a study of influenza dynamics, county and state-wide. These partnerships have gained us access to disaggregate data on the appearance of influenza in the Allegheny county community. The intersection of experience conducting school-based influenza surveillance, developing novel statistical tools to study spatial-temporal dynamics of infectious diseases and long standing relationships with local public health authorities position us extremely well to succeed in this project. Dr. Derek Cummings is the Principal Investigator of this proposal, and each of the co-investigators has extensive experience working and collaborating with him on other research projects. Dr. Zimmer is an infectious disease clinician who has performed studies of the community transmission and burden of influenza in the 2009 pandemic and of influenza in interpandemic periods. Mr. Vukotich has extensive experience in public health project management stemming from 30 years of work at the Allegheny County Health Department (ACHD) as Assistant Deputy Director. We aim to develop protocols for conducting cause-specific school absence surveillance that can be transported to other populations, develop predictive models of the temporal course of influenza in communities and schools and develop novel statistical methods for prediction.